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1.
Holm oak is the hardwood most used for reforestation in Mediterranean Spain, which makes the development of stock quality standards in order to improve establishment success, a priority. However, its nursery culture is characterized by a wide range of practices resulting in stock heterogeneity and a potentially varied outplanting performance. Previous research has focused on specific seedling quality attributes, obviating the integral effect of nursery culture on overall quality. We studied growing regime, seedling quality, and field performance in nine holm oak stocklots produced in commercial nurseries during two consecutive growing years. Results proved variations in field performance were related to stocklot quality and, hence, to the growing regime practised. This dependence on stock quality may vary with planting site weather: in the drier year, survival was related to attributes like height, water status and K concentration, while, in the second, milder year, only growth performance was related to nutrient concentrations, plant size and water status. Results indicated the following quality standards for height: 12–17 cm, diameter: 3.5–4.8 mm, shoot and root weights: 1.3–1.6 and 2.8–4.7 g, respectively, N–P–K foliar concentrations: over 10–0.9–3.7 mg g−1, respectively and in water status parameters: EMX < 5 MPa and SWDTL > 15%. These attributes can be adjusted using nursery cultural practices in order to meet seedling quality standards for holm oak for planting across similar sites.  相似文献   

2.

• Introduction   

For Holm oak (Quercus ilex L.), a flush growing species, nutrient loading during the growing season is difficult and can lead to a low nutrient status of the seedlings. To provide insights about Holm oak nutrient dynamics during fall in the nursery and subsequent planting performance, a factorial nursery experiment was conducted in a mild fall–winter area testing the effects of timing of fertilization (early and late fall) and rate (two doses of a NPK fertilizer that applied 28 and 56 mg N per seedling), followed by an experimental plantation.  相似文献   

3.
Current policy in Ireland calls for increased quality and quantity of broadleaved seedling plantings. Simultaneously, concerns regarding environmental contamination necessitate development of nursery production methods that minimize impacts. Exponential (E) fertilization has potential for producing high-quality seedlings through nutrient loading, while simultaneously minimizing nitrogen (N) losses during culture. We investigated the effects of a wide range (0.10–1.0 g N seedling−1 year−1) of E fertilization rates on seedling morphology and nutrition of Quercus robur L., as well as soil N status and N budget during one growing season in a bareroot nursery in County Carlow, Ireland. The N budget showed significant N losses, especially in the highest fertilizer treatments, due to high precipitation. Seedlings receiving the 0.5 E rate were morphologically and nutritionally superior to all other treatments. Results indicate that it may be possible to produce 1-0 bareroot seedlings meeting target specifications in Ireland and other countries of similar climate and soils if further manipulations to seedling culture are implemented; however, potential environmental degradation via N leaching must be considered when N loading in wet years.  相似文献   

4.
We tested the effects of exponential nutrient loading and springtime carbon loading during nursery culture on the field performance of black spruce (Picea mariana (Mill.) B.S.P.). Seedlings were grown from seed with a conventional, fixed dose fertilizer (10 mg N seedling−1) or an exponential nutrient loading regime (75 mg N seedling−1). The following spring, seedlings were exposed for two weeks to either ambient (370 ppm) or elevated levels of CO2 (800 ppm) and then planted in the field; seedling growth was followed for the next six years. Exponential nutrient loading increased seedling height, stem diameter and leader growth, with the largest increases in height and leader length occurring in the first three years after outplanting. Carbon loading increased seedling height and leader length, but only in seedlings that had been exponentially nutrient loaded. A combination of carbon and nutrient loading increased shoot height 26%, stem diameter 37% and leader length 40% over trees that received neither treatment. These results demonstrate that the growth enhancement seen under exponential nutrient loading is maintained under field conditions for at least six years. Carbon loading just before outplanting was a useful supplement to nutrient loading, but was ineffective in the absence of nutrient loading.  相似文献   

5.
Abstract

Exponential nutrient loading has been used to improve nursery fertilizer uptake efficiency of conifer seedlings, but the technique has received little attention in the culture of temperate deciduous hardwoods. This study examined responses of northern red oak (Quercus rubra L.) and white oak (Q. alba L.) seedlings to modified exponential nitrogen loading during bareroot nursery culture using a broad range of nutrient supply from 0 to 3.35 g nitrogen (N) per plant per season for 18 weeks in Indiana, USA. Seedling growth and nutritional parameters followed a curvilinear pattern that ranged from deficiency to toxicity with increased fertilization consistent with trends depicted in the proposed model for nutrient loading. Fertilization increased plant dry mass by 113–260% for red oak and 49–144% for white oak. Severe nutrient deficiency occurred under indigenous soil fertility, and limited phosphorus and potassium uptake were found to inhibit seedling growth at higher N supply. The sufficiency and optimum rates were determined to be 0.84 and 1.68 g N per seedling per season, respectively, under the current cultural conditions. Fertilization at 1.68 g N per plant increased N content by 40% in red oak and 35% in white oak. This approach may be used to help refine nursery fertilization practices in hardwood culture to produce high-quality seedlings for field planting.  相似文献   

6.
In Mediterranean arid regions, relatively small planting stock has traditionally been used in an attempt to reduce drought susceptibility, though few studies have examined influences of initial seedling morphology and nutrition on long-term plantation establishment. We fertilized Pinus halepensis Mill. seedlings in the nursery with controlled release fertilizer (CRF) varying in formulations and rates; 9-13-18 and 17-10-10 (N-P-K) formulations at 3, 5 and 7 g l−1 substrate plus an unfertilized control and we evaluated growth and survival 7 years after planting in arid conditions in Almería province, southeast Spain. Interactions between initial height and fertilizer treatments occurred during the first 3 years; initial size advantages of specific fertilizer treatments (7 g l−1 of 9-13-18 and 17-10-10 at 3 g l−1) persisted after 7 years. The largest and most nutrient-rich seedlings from 9-13-18 at 7 g l−1 (41.0 cm tall, 4.4 mg of P per g of root tissue at time of planting) exhibited the highest survival after 7 years (79%), while survival declined to 42% for non-fertilized plants (12.9 cm tall and 0.6 mg of P per g of root tissue). Initial seedling morphological parameters were most consistently correlated with field performance. Root P concentration was the nutrient variable most closely related to survival. Our data emphasizes importance of longer-term experiments to accurately assess influences of nursery treatments on field responses, particularly in arid areas. We suggest that larger seedlings with greater nutrient reserves than are currently being used should be incorporated into Mediterranean plantations.  相似文献   

7.
[目的]探讨控释肥和灌溉方式对栓皮栎(Quercus variabilis Bl.)容器苗生长、养分含量、基质电导率(EC)及2年造林效果的影响,为培育高质量苗木提供参考。[方法]以栓皮栎容器苗为研究对象,采用双因素完全随机试验设计,设置5个施肥水平(以N元素含量为基准,5个施肥水平分别为:25、75、125、175、225 mg·株~(-1))和2种灌溉方式(上方喷灌(O)、底部渗灌(S)),测定栓皮栎容器苗形态指标、养分含量、根系生长、基质EC值及连续2年造林效果。[结果]表明:(1)施肥量和灌溉方式二者对苗木形态指标影响存在交互效应,225-O处理的苗木地径、根生物量、单株生物量最大,但根生物量、单株生物量在225-O、125-S、175-O处理之间差异不显著。225-S处理的苗高、茎生物量、茎根比最大,茎生物量在225-S与225-O之间差异不显著。(2)苗木茎、根的氮磷钾浓度和含量随施肥量的增加而增大,施肥量125、175、225 mg·株~(-1)处理之间的根氮、磷含量及单株磷含量差异不显著。(3)增加施肥量促进苗木根系的生长,施肥量为125、175、225 mg·株~(-1)处理之间的根系表面积、体积差异不显著。(4)基质EC值随施肥量的增加而增大,底部渗灌显著提高了基质上层、下层的EC值,基质上层、下层的最大EC值分别为4. 69、0. 56d S·m-1,没有对苗木生长产生不利影响。(5)和上方喷灌相比,底部渗灌显著地促进造林第1年幼树的树高、地径生长;造林第1年、第2年的树高和地径均随施肥量的增加而增大,造林第2年,施肥量125、175、225 mg·株~(-1)处理之间的树高、地径差异不显著。[结论]底部渗灌提高了栓皮栎容器苗体内的养分含量,促进了造林第1年幼树树高、地径的生长。施加控释肥有利于苗期苗木质量的提高及造林后苗木的快速生长。综合考虑苗木质量、经济效益、环境利益,培育栓皮栎容器苗可选择底部渗灌和控释肥量为125 mg·株~(-1)的组合(以N元素含量为基准)。  相似文献   

8.
Nutrient loading of nursery seedling stock of species with an indeterminate growth strategy is challenging and poorly understood. Here, we explore the use of two potential techniques for nutrient loading of trembling aspen (Populus tremuloides Michx.) seedlings: (1) exponential fertilization and (2) early shoot growth termination in order to divert assimilated nutrients and carbon to storage rather than to growth. In the first study, aspen seedlings were treated with either exponential or constant fertilization rates, both of which supplied the same amount of nutrients over the growing season. Exponential fertilization resulted in overall poor planting stock form (stunted seedling growth and weak root development) and produced only marginal improvements of nutrient status. As a result, the exponential fertilization regime studied cannot be recommended as a treatment for aspen seedlings. In the second study we treated seedlings with a 2 × 2 factorial combination of fertilization and shoot growth inhibitor (SGI) applications with the fertilizer treatments varying in terms of mid-season fertilizer concentrations. Seedlings with SGI application had much higher tissue nutrient and carbon reserve concentrations than seedlings without a SGI application. In addition, nutrient uptake appeared to be more efficient in SGI treated seedlings, which could potentially result in significant reductions of nutrient application rates during aspen seedling production in nurseries. Overall, early shoot growth termination using a SGI appears to be an effective technique to produce nutrient loaded aspen seedlings.  相似文献   

9.
Bareroot Changbai larch (Larix olgensis Henry.) seedlings were reared with inorganic fertilizer (nitrogen (N):phosphorus (P) = 1:1, W/W) applied at a rate of 100 (F100) or 200 kg N ha−1 (F200) with (+) or without (−) chicken manure as a soil amendment (O) in north-eastern China. An unfertilized control treatment was included. Inorganic and organic fertilizer treatments tended to increase soil ammonium, nitrate, available P, total P, organic carbon content and electrical conductivity, and biomass and N concentration in seedlings. Organic amendment improved first order lateral root number, tap root length, fine root morphology (length, surface area, volume) in seedlings, while the F100 treatment increased N accumulation in needles and stems compared to the F200 treatment, on average. Most fertilizer treatments tended to increase P content in combined stems and roots, but F200 − O and F100 + O treatments diluted P in needles. Organic amendment combined with inorganic fertilizer at a rate of 100 kg N and P ha−1 is recommended to improve seedling growth and N reserves in woody tissues.  相似文献   

10.
Mycorrhizal and non-mycorrhizal holm oak (Quercus ilex L.) seedlings inoculated with black truffle (Tuber melanosporum) were grown under nursery conditions and subjected to drought hardening for 4 months in autumn and winter followed by irrigation for 10 days. Leaf water potential and stomatal conductance were monitored during the 4 months of drought. When the test was completed (March), measurements were made for each treatment (inoculated or non-inoculated), and watering regime (watered and water-stressed). Pressure–volume curves, osmotic potential at full turgor, osmotic potential at zero turgor and the tissue modulus of elasticity near full turgor were calculated. Mycorrhizal colonization and growth, and the content of the main mineral nutrients N, P, K, Ca and Mg were measured. Water stress affected plant growth, caused an elastic adjustment of the plant tissues, and decreased the P and K content, and inoculation improved the nitrogen content. Drought acclimation apparently achieved the goal of improving the drought tolerance of holm oak seedlings, without depressing ectomycorrhizal root colonization by T. melanosporum. José Antonio Rodríguez Barreal—Deceased  相似文献   

11.

Ruil (Nothofagus alessandrii) is an endangered keystone species from the Mediterranean climate zone of Chile. Ruil’s fragile state of conservation urges development of restoration programs, but specific protocols for nursery production and field establishment that ensure plant survival are largely unknown. Therefore, we examined the effect on nitrogen (N) fertilization and container size during nursery production in combination with the use of mesh shelters after outplanting on survival and growth during the first growing season in the field. First year outplanting survival of nursery-grown container seedlings was enhanced when seedlings were given nitrogen (N) during nursery production and deployed with mesh tree shelters in the field. The volume of the container had no effect on outplanting survival and growth. Increasing N from zero to 200 mg N L?1 provided sufficient N levels, resulting in increased seedling height, root-collar diameter, shoot biomass, and total seedling N and phosphorous concentrations. Additional N provided by the 400 and 600 mg N L?1 treatments underwent luxury consumption by the seedlings with no further benefits in field performance. Improved growth in the nursery, along with the use of mesh tree shelters after outplanting, especially during the typical summer drought, may be responsible for increased survival during the first growing season. Increasing the performance of nursery-grown ruil seedlings is essential to restoring this endangered, vulnerable, and foundation species within the highly biodiverse, yet seriously threatened endemic Maulino Costero Forest of the Mediterranean climate of central Chile.

  相似文献   

12.
The low availability of nitrogen (N) is believed to be one of the major limiting factors of forest regeneration in Iceland and frequently under Boreal conditions. Lutz spruce (Picea x lutzii Littl.) seedlings were nutrient loaded using four fertilization regimes in the end of nursery rotation in autumn 2008 and planted in the following spring, with or without a single dose of fertilizer, on two treeless sites in N-Iceland with contrasting soil fertility. Measurements were made after one growing season. The highest loading level without additional field fertilization increased new needle mass by 122% and 152%, for the poor and more fertile site, respectively. The highest loading level with field fertilization increased new needle mass equally, by 188% and 189%, for the poor and more fertile site, respectively. Retranslocation of N, from old needles to current needles, increased with more loading. However, it was clear that nutrient loading could not replace field fertilization, as the seedlings generally showed an additive response to field fertilization and nutrient loading; doing both always gave the best results in seedling performance. As the study only covers field establishment during the first year, the long-term effect of nutrient loading of Lutz spruce cannot be predicted. However, it was concluded that loading might provide an additional input for faster plantation establishment during the first growing season after planting.  相似文献   

13.
We report an efficient in vitro propagation method for Terminalia catappa using nodal segments of a 15-year-old mature tree. The nodal segments were cultured on MS medium supplemented with 6-benzyladenine (BA; 0.5–3.0 mg l−1) or Kinetin (Kn; 0.5–3.0 mg l−1) for bud breaking and multiple shoot induction. About 85% of the explant responded (2.8 ± 0.41 shoots per node with 2.7 ± 0.14 cm length) within 15 days of inoculation in Murashige and Skoog medium fortified with 2.0 mg l−1 of BA. Further shoot multiplication was achieved by repeated transfer of mother explants and subculturing of in vitro-produced shoots on medium supplemented with various concentrations of BA (0.25–1.5 mg l−1) or Kn (0.25–1.5 mg l−1) or on their combinations. Optimal number of shoots and shoot length were recorded on MS medium supplemented with 0.25 mg l−1 of BA and 0.25 mg l−1 of Kn. The multiplied shoots were used for ex vitro rooting after treatment for 4 min with indole-3-butyric acid (IBA; 50–500 mg l−1) or α-naphthalene acetic acid (NAA; 50–500 mg l−1). About 80% of the shoots treated with 200 mg l−1 of IBA produced ex vitro roots with an average of 2.8 roots per shoot. Nearly 75% of these plantlets could be acclimatized within 5 weeks and successfully established in the field. This is the first report on micropropagation of T. catappa, which can be applied for further genetic transformation assays and pharmaceutical purposes.  相似文献   

14.
The emergence and survival of pregerminated holm oak (Quercus ilex) and cork oak (Quercus suber) acorns from two ecologically different dehesas (Mediterranean open woodlands) were studied in two soils from these stands naturally infected with Phytophthora cinnamomi, and in the same soils previously sterilized in the autoclave. Phytophthora cinnamomi was consistently isolated from the radicles of all unemerged and all emerged but dead seedlings from the unsterilized substrates. Seedlings of holm oak were more susceptible to P. cinnamomi than those of cork oak. Mortality of holm oak seedlings was significantly different depending only on soil treatment (sterilized or unsterilized), and it was 100% in unsterilized soils, independent of acorn provenance and soil origin. Mortality of cork oak seedlings was significantly different depending on the acorn origin and soil treatment, and on the interactions acorn origin × soil origin and soil origin × soil treatment. The demonstrated high susceptibility of holm and cork oak young seedlings to P. cinnamomi could be a limiting factor in Mediterranean open woodlands (dehesas) not only in natural regeneration processes but also when reforestation by direct sowing is implemented.  相似文献   

15.
Tree-based intercropping (TBI) systems, combining agricultural alley crops with rows of hardwood trees, are largely absent in Canada. We tested the hypothesis that the roots of 5–8 years old hybrid poplars, growing in two TBI systems in southern Québec, would play a “safety-net” role of capturing nutrients leaching below the rooting zone of alley crops. TBI research plots at each site were trenched to a depth of 1 m on each side of an alley. Control plots were left with tree roots intact. In each treatment at each site, leachate at 70 cm soil depth was repeatedly sampled over two growing seasons using porous cup tension lysimeters, and analyzed for nutrient concentrations. Daily water percolation rates were estimated with the forest hydrology model ForHyM. Average nutrient concentrations for all days between consecutive sampling dates were multiplied by water percolation rates, yielding daily nutrient leaching loss estimates for each sampling step. We estimated that tree roots in the TBI system established on clay loam soil decreased subsoil NO3 − leaching by 227 kg N ha−1 and 30 kg N ha−1 over two consecutive years, and decreased dissolved organic N (DON) leaching by 156 kg N ha−1 year−1 in the second year of the study. NH4 + leaching losses at the same site were higher when roots were present, but were 1–2 orders of magnitude lower than NO3 − or DON leaching. At the sandy textured site, the safety net role of poplar roots with respect to N leaching was not as effective, perhaps because N leaching rates exceeded root N uptake by a wider margin than at the clay loam site. At the sandy textured site, significant and substantial reductions of sodium leaching were observed where tree roots were present. At both sites, tree roots reduced DON concentrations and the ratio of DON to inorganic N, perhaps by promoting microbial acquisition of DON through rhizodeposition. This study demonstrated a potential safety-net role by poplar roots in 5–8 year-old TBI systems in cold temperate regions.  相似文献   

16.
In this study, the supply and input–output balances of phosphorus (P) were investigated for a 10-year-period at 85 long-term monitoring sites in German forest ecosystems under the European Level II programme. These sites encompass 23 European beech (Fagus sylvatica L.) stands, 9 oak stands comprised of common oak (Quercus robur L.) and/or sessile oak (Quercus petraea Liebl.), 20 Scots pine (Pinus sylvestris L.) and 33 Norway spruce (Picea abies H.Karst.) stands. We quantified P concentrations in needles and leaves, P inputs from the atmosphere, P outputs through leaching and harvesting, and total P in the soil and humus layers. The P concentrations in European beech leaves from two sites (>1 mg P g−1 dry weight), and in Norway spruce needles from four sites (>1.2 mg P g−1 dry weight), were deficient over several years. In contrast, the oak and Scots pine sites were well supplied with P. When P removal through harvesting was disregarded, P balances were positive or stable (median 0.21 kg P ha−1 a−1). With harvesting, balances were mostly negative (median −0.35 kg P ha−1 a−1), with long-term P removal from the forest ecosystems.  相似文献   

17.
Severe environmental problems encountered in the highlands of Bolivia may be remedied through the adoption of agroforestry systems, never before studied adequately in this region. As a first step, seven tree species were tested for growth, survival and health at two elevations in the Bolivian altiplano. Species responded variably with Buddleja coriacea Remy., Pinus radiata D. Don. and Eucalyptus globulus Labill. (at the higher elevation) and E. globulus, Baccharis spp., Robinia pseudoacacia L. and B. coriacea (at the lower elevation), displaying high survival, growth and health. In a related greenhouse study, grain yields of wheat planted in soils amended with incorporated foliage of B. coriacea, P. radiata and E. globulus increased three-fold (0.3 g·plant−1 to >1.0 g·plant−1) over grain yields in unamended soils (B. coriacea > P. radiata = E. globulus). Grain nitrogen (mg·plant−1) increased equally in soils amended with P. radiata and B. coriacea foliage (18 mg N⋅plant−1 to 20 mg·plant−1) but decreased in soils amended with foliage of E. globulus (18 g·plant−1 to 9 g·plant−1). This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

18.
The effect of shoot pruning on leaf phenology, stem wood anatomy and sap flow was investigated on Senna spectabilis (DC.) Irwin and Barneby in Machakos, Kenya. Unpruned trees (single stem) were compared to hedges (two to four stems), pruned 4 times a year during two rainy seasons (April–June, 1997 and November, 1997–January, 1998) separated by a dry season (July–October 1997). Trees attained peak leaf area of 55 m2 plant−1 during the rainy seasons, and shed all their leaves naturally during the dry season. Maximum hedge leaf area was 4 m2 plant−1 between pruning events and 5.2 m2 plant−1 during the dry season. Pruning induced multiple stems and narrow xylem vessels with low hydraulic conductivity. Average cross sectional area of conducting wood per plant was at least 1.8 times greater in trees than in hedges. Xylem lumen diameter at 5 mm depth below the cambium was significantly (P < 0.001) larger in trees (53.6 ± 6.21 μm) than that in hedges (36.2 ± 8.21 μm). Maximum sap flow occurred in the wet season for trees (4800 g d−1 plant−1) and in the dry season for hedges (1400 g d−1 plant−1). Wet season pruning suppressed crown expansion and modified the natural phenology of senna, reducing transpiration rate and therefore soil water depletion, causing crowns to grow. This enhanced the ecological combining ability of senna managed as hedges with annual crops.  相似文献   

19.
Forest restoration projects with Holm oak (Quercus ilex) have had limited success, mostly due to water stress after planting and poor plant quality. Recent studies indicated that large and nutrient rich plants perform better in Mediterranean areas, suggesting that late-season fertilization may improve plant quality and field performance. The purpose of this study was to assess the effect of late-season fertilization on the quality of Holm oak seedlings, as determined by morphological, nutritional, and water relations analyses. We grew Holm oak nursery seedlings under 5 different late-season fertilization regimes and then analyzed morphological characteristics, nutritional status, and water relations parameters of the fertilization groups at the end of the nursery period. We also analyzed the effect of fertilization on nutritional status by use of vector nomograms. Our results indicated that late-season NPK fertilization improved shoot and root growth, and the overall nutritional status of seedlings. The lack of late-season fertilization leads to nutrient deficiency in plants, whilst the application of imbalanced fertilization treatments may trigger nutrient luxury consumption and nutrient dilution, pointing out the importance of NPK proportions in the fertilizer. Moreover, late-season fertilization with nitrogen might improve the drought resistance of seedling by enhancing their osmotic adjustment.  相似文献   

20.
Shade tolerant species response to nutrient additions and light regulation by canopy trees in perennial agroforestry systems has been well documented. However, accelerated early growth, particularly in cocoa-shade systems, may be offset by competition for limited resources on nutrient poor sites. To date, few agroforestry management strategies focus on nutrient manipulation of the shade tree component or strategies for precision nutrient application. Our research objective was to diagnose interactions between nutrient supplied shade trees intercropped with cocoa. We established greenhouse trials in Kwadaso, Ghana cultivating Terminalia superba seedlings with four fertility treatment levels: conventional rate (current practices) under linear additions, and half, full and double conventional rate under exponential additions (steady-state nutrition) to determine maximal growth and nutrient uptake. After 4 months of additions in the nursery, pre-fertilized T. superba seedlings were then out-planted into field trials with cocoa seedlings. After 4 months of intercropping, cocoa associated with half rate exponentially supplied T. superba had significantly larger leaf area, greater leaf number, and higher nutrition (N and P uptake) than cocoa associated with full rate conventionally supplied T. superba. This may be attributed to (1) more favorable light conditions under these taller shade seedlings and (2) the internal use of nutrients associated with exponentially supplied T. superba seedlings, which lowered stress on native soil resources. The latter is corroborated with our findings on soil fertility status. This strategy focused on reducing fertilizer inputs and developing precise plant nutrition technology for on-farm use. Our findings suggest that shade seedlings under steady state nutrition can mitigate early growth competition in the field.  相似文献   

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